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Articles 1 - 18 of 18
Full-Text Articles in Physical Sciences and Mathematics
Jamming Detection And Classification In Ofdm-Based Uavs Via Feature- And Spectrogram-Tailored Machine Learning, Y. Li, J. Pawlak, J. Price, K. Al Shamaileh, Q. Niyaz, S. Paheding, V. Devabhaktuni
Jamming Detection And Classification In Ofdm-Based Uavs Via Feature- And Spectrogram-Tailored Machine Learning, Y. Li, J. Pawlak, J. Price, K. Al Shamaileh, Q. Niyaz, S. Paheding, V. Devabhaktuni
Michigan Tech Publications
In this paper, a machine learning (ML) approach is proposed to detect and classify jamming attacks against orthogonal frequency division multiplexing (OFDM) receivers with applications to unmanned aerial vehicles (UAVs). Using software-defined radio (SDR), four types of jamming attacks; namely, barrage, protocol-aware, single-tone, and successive-pulse are launched and investigated. Each type is qualitatively evaluated considering jamming range, launch complexity, and attack severity. Then, a systematic testing procedure is established by placing an SDR in the vicinity of a UAV (i.e., drone) to extract radiometric features before and after a jamming attack is launched. Numeric features that include signal-to-noise ratio (SNR), …
Identification Of Nonlinear Channels In Bandpass Communication Systems With Ofdm Inputs, Jen-Ho Cheng, Ching-Hsiang Tseng
Identification Of Nonlinear Channels In Bandpass Communication Systems With Ofdm Inputs, Jen-Ho Cheng, Ching-Hsiang Tseng
Journal of Marine Science and Technology
A general approach to the derivation of simple yet accurate formulas for identifying bandpass nonlinear channels in or-thogonal frequency-division multiplexing (OFDM) systems is proposed in this paper. The OFDM is an widely adopted tech-nique for wideband communication applications. An OFDM signal could be highly vulnerable to nonlinearities in a com-munication link. This makes proper estimation of the nonlin-ear channel essential for an OFDM system. A nonlinear bandpass communication channel is commonly described by a complex Voletrra series, in which the task of nonlinear channel identification is to determine the Volterra kernels. This task can become very difficult when the order …
Low Complexity Method Based On Fc-Ce-Slm For Papr Reduction In Ofdm System, Ce Ji, Lijuan Wang
Low Complexity Method Based On Fc-Ce-Slm For Papr Reduction In Ofdm System, Ce Ji, Lijuan Wang
Journal of System Simulation
Abstract: Selected mapping (SLM) algorithm uses Cross Entropy (CE) algorithm to get the most optimal sign sequence so that SLM can make the effect of PAPR Reduction achieve optimum. However, it needs too many times iterative computations, so it will increase the complexity of the algorithm. In order to solve this problem, a fast convergence factor in the CE-SLM algorithm was introduced to make the sampling probability converge to 0 or 1 quickly in the system, which reduced the iterative times of getting the optimal sign sequence. Computer simulation results show that the approved algorithm reduces the iterative times of …
Low-Power Wide-Area Network Design, Md Mahbubur Rahman
Low-Power Wide-Area Network Design, Md Mahbubur Rahman
Wayne State University Dissertations
Low-Power Wide-Area Network (LPWAN) is an enabling technology for long-range, low-power, and low-cost Internet of Things (IoT) and Cyber-Physical Systems (CPS) applications. Due to their escalating demand in the IoT/CPS applications, recently, multiple LPWAN technologies have been developed that operate in the cellular/licensed (e.g., 5G, LTE Cat M1, and NB-IoT) and unlicensed/ISM (e.g., LoRa and SigFox) bands. To avoid the crowd in the limited ISM band (where most LPWANs operate) and the cost of the licensed band, we propose a novel LPWAN technology called Sensor Network Over White Spaces (SNOW) by utilizing the TV white spaces. White spaces refer to …
Feasibility And Security Analysis Of Wideband Ultrasonic Radio For Smart Home Applications, Qi Xia
Feasibility And Security Analysis Of Wideband Ultrasonic Radio For Smart Home Applications, Qi Xia
Department of Computer Science and Engineering: Dissertations, Theses, and Student Research
Smart home Internet-of-Things (IoT) accompanied by smart home apps has witnessed tremendous growth in the past few years. Yet, the security and privacy of the smart home IoT devices and apps have raised serious concerns, as they are getting increasingly complicated each day, expected to store and exchange extremely sensitive personal data, always on and connected, and commonly exposed to any users in a sensitive environment. Nowadays wireless smart home IoT devices rely on electromagnetic wave-based radio-frequency (RF) technology to establish fast and reliable quality network connections. However, RF has its limitations that can negatively affect the smart home user …
An Efficient Ofdm-Based System With An Insufficient Cyclic Prefix Via A Novel Constellation Algorithm, Saeed Ghazi-Maghrebi
An Efficient Ofdm-Based System With An Insufficient Cyclic Prefix Via A Novel Constellation Algorithm, Saeed Ghazi-Maghrebi
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, a new special triangular constellation scheme is introduced to replace the commonly used rectangular QAM constellation in orthogonal frequency division multiplexing (OFDM) modulation. We have shown that this new scheme has 3 major advantages with respect to the well-known QAM. The first advantage is its lower error probability performance, which results from better usage of the constellation space with longer minimum distances. The 2 other advantages are a lower peak to average power ratio (PAPR) and higher noise immunity. Both mathematical analysis and simulation results demonstrate that by applying standard channels in 2 cases, i.e. channels with …
Stc-Mimo Block Spread Ofdm In Frequency Selective Rayleigh Fading Channels, Le Chung Tran, Xiaojing Huang, Eryk Dutkiewicz, Joe F. Chicharo
Stc-Mimo Block Spread Ofdm In Frequency Selective Rayleigh Fading Channels, Le Chung Tran, Xiaojing Huang, Eryk Dutkiewicz, Joe F. Chicharo
Dr Le Chung Tran
In this paper, we expand the idea of spreading the transmitted symbols in OFDM systems by unitary spreading matrices based on the rotated Hadamard or rotated Discrete Fourier Transform (DFT) matrices proposed in the literature to apply to Space-Time Coded Multiple-Input Multiple-Output OFDM (STC-MIMO-OFDM) systems. We refer the resulting systems to as STC-MIMO Block Spread OFDM (STC-MIMO-BOFDM) systems. In the proposed systems, a multi-dimensional diversity, including time, frequency, space and modulation diversities, can be used, resulting in better bit error performance in frequency selective Rayleigh fading channels compared to the conventional OFDM systems with or without STCs. Simulations carried out …
On The Use Of Quasi-Orthogonal Space-Time-Frequency Codes In Mb-Ofdm Uwb, Le Chung Tran, Alfred Mertins
On The Use Of Quasi-Orthogonal Space-Time-Frequency Codes In Mb-Ofdm Uwb, Le Chung Tran, Alfred Mertins
Dr Le Chung Tran
Space-Time-Frequency Codes (STFCs), which haverecently been proposed in the literature for Multiband OFDMUltra-Wideband (MB-OFDM UWB) systems to improve thesystem capacity, error performance and wireless communicationrange, are all constructed based on orthogonal structures. Thispaper examines the application of Quasi-Orthogonal STFCs(QOSTFCs) to enhance further either data rate or error performancein the recently proposed STFC MB-OFDM UWB systems.It will be shown that QOSTFCs can provide significantly bettererror performance, compared to the conventional MB-OFDMUWB (without STFCs) as well as to the Orthogonal STFCs(OSTFCs) of the same order, at the same data rate, withoutincreasing the total transmission power. Equivalently, QOSTFCscan provide higher data rates with …
Rate 1 Space-Time And Space-Frequency Spreading Diversity Technique, Gökçe Hacioğlu, Ali̇ Gangal
Rate 1 Space-Time And Space-Frequency Spreading Diversity Technique, Gökçe Hacioğlu, Ali̇ Gangal
Turkish Journal of Electrical Engineering and Computer Sciences
In this study, a rate 1 transmitter diversity technique is proposed. The proposed technique uses spreading transform and space-time block coding (STBC) together. Space-time, space-frequency, and frequency diversity applications of the proposed technique are shown. The code matrix of the proposed technique can be designed systematically. The proposed technique needs the channel coefficients to stay constant over transmission of 2 rows of the coding matrix regardless of the size of the coding matrix or the diversity order. However, joint detection of the symbols is required for the proposed technique. We used computer simulations to compare our technique with the quasi-orthogonal …
A Heuristic Scheduling Scheme In Multiuser Ofdma Networks, Zheng Sun, Zhiqiang He, Ruochen Wang, Kai Niu
A Heuristic Scheduling Scheme In Multiuser Ofdma Networks, Zheng Sun, Zhiqiang He, Ruochen Wang, Kai Niu
Zheng Sun
Conventional heterogeneous-traffic scheduling schemes utilize zero-delay constraint for real-time services, which aims to minimize the average packet delay among real-time users. However, in light or moderate load networks this strategy is unnecessary and leads to low data throughput for non-real-time users. In this paper, we propose a heuristic scheduling scheme to solve this problem. The scheme measures and assigns scheduling priorities to both real-time and non-real-time users, and schedules the radio resources for the two user classes simultaneously. Simulation results show that the proposed scheme efficiently handles the heterogeneous-traffic scheduling with diverse QoS requirements and alleviates the unfairness between real-time …
Multipath Diversity Of Precoded Ofdm With Linear Equalization, Xiaojing Huang
Multipath Diversity Of Precoded Ofdm With Linear Equalization, Xiaojing Huang
Faculty of Informatics - Papers (Archive)
This paper settles a controversy over the multipath diversity performance of the precoded orthogonal frequency division multiplexing system with the linear equalization. Through the asymptotical analysis of the bit error rates with extreme system parameters, a comprehensive understanding of the linear equalization's behavior in the frequency-selective multipath fading channels is gained. Compared with the optimum maximum-likelihood detection, the diversity performance of the linear equalization can be well described by an asymptotical signal-to-noise ratio (SNR) degradation, which reveals that the linear equalization can achieve the maximum multipath diversity within an operational SNR range but will lose diversity advantage as SNR increases.
On The Use Of Quasi-Orthogonal Space-Time-Frequency Codes In Mb-Ofdm Uwb, Le Chung Tran, Alfred Mertins
On The Use Of Quasi-Orthogonal Space-Time-Frequency Codes In Mb-Ofdm Uwb, Le Chung Tran, Alfred Mertins
Faculty of Informatics - Papers (Archive)
Space-Time-Frequency Codes (STFCs), which haverecently been proposed in the literature for Multiband OFDMUltra-Wideband (MB-OFDM UWB) systems to improve thesystem capacity, error performance and wireless communicationrange, are all constructed based on orthogonal structures. Thispaper examines the application of Quasi-Orthogonal STFCs(QOSTFCs) to enhance further either data rate or error performancein the recently proposed STFC MB-OFDM UWB systems.It will be shown that QOSTFCs can provide significantly bettererror performance, compared to the conventional MB-OFDMUWB (without STFCs) as well as to the Orthogonal STFCs(OSTFCs) of the same order, at the same data rate, withoutincreasing the total transmission power. Equivalently, QOSTFCscan provide higher data rates with …
Higher Order Parallel Concatenated Spreading Matrices Ofdm, Xiaojing Huang, Ibrahim Raad
Higher Order Parallel Concatenated Spreading Matrices Ofdm, Xiaojing Huang, Ibrahim Raad
Faculty of Informatics - Papers (Archive)
This paper studies higher order parallel concatenated spreading matrix OFDM (PCSM-OFDM). PCSM-OFDM was shown to greatly improve on the classic Block Spread OFDM, this paper continues the work on PCSM-OFDM and studies higher order in terms of an increased number of streams. This shows that with the increase in the streams the overall BER performance improves.
A Study Of Different Angles For Higher Order Rotation Spreading Matrix For Bsofdm In Uwb Channels, Ibrahim S. Raad, Xiaojing Huang, R. Raad
A Study Of Different Angles For Higher Order Rotation Spreading Matrix For Bsofdm In Uwb Channels, Ibrahim S. Raad, Xiaojing Huang, R. Raad
Faculty of Informatics - Papers (Archive)
This paper presents a study into different angles for higher order Rotation spreading matrix developed for BSOFDM. It was shown previously that for block size M = 2 that the angle α = π/3 achieved the best result in terms of BER in UWB channels. It was discovered that this was no longer the case when the higher order Rotation spreading matrix was used for larger M sized blocks and that other angles produced better results which proves that the Rotation spreading matrix advantage over existing spreading matrices such as the Hadamard is its flexibility to be adapted to different …
Stc-Mimo Block Spread Ofdm In Frequency Selective Rayleigh Fading Channels, Le Chung Tran, Xiaojing Huang, Eryk Dutkiewicz, Joe F. Chicharo
Stc-Mimo Block Spread Ofdm In Frequency Selective Rayleigh Fading Channels, Le Chung Tran, Xiaojing Huang, Eryk Dutkiewicz, Joe F. Chicharo
Faculty of Informatics - Papers (Archive)
In this paper, we expand the idea of spreading the transmitted symbols in OFDM systems by unitary spreading matrices based on the rotated Hadamard or rotated Discrete Fourier Transform (DFT) matrices proposed in the literature to apply to Space-Time Coded Multiple-Input Multiple-Output OFDM (STC-MIMO-OFDM) systems. We refer the resulting systems to as STC-MIMO Block Spread OFDM (STC-MIMO-BOFDM) systems. In the proposed systems, a multi-dimensional diversity, including time, frequency, space and modulation diversities, can be used, resulting in better bit error performance in frequency selective Rayleigh fading channels compared to the conventional OFDM systems with or without STCs. Simulations carried out …
Decision Aided Joint Compensation Of Clipping Noise And Nonlinearity For Mimo-Ofdm Systems, Shouyi Yang, Jiangtao Xi, Xiaomin Mu
Decision Aided Joint Compensation Of Clipping Noise And Nonlinearity For Mimo-Ofdm Systems, Shouyi Yang, Jiangtao Xi, Xiaomin Mu
Faculty of Informatics - Papers (Archive)
In this paper, we propose a new iterative approach to compensate the nonlinearity and clipping noise in multi-input multi-output orthogonal frequency division multiplexing (MlMO-OFDM) system with nonlinear channel. The proposed approach consists of two stages. Firstly a decision aided method is proposed to eliminate the nonlinearity introduced by high power transmit amplifier (HPA). Then this improved decision observations are employed to achieve the clipping noise compensation. The effectiveness of the proposed approach has been verified by computer simulations.
An Adaptive Scalable Multiuser-Ofdm System For Multimedia Transmission Over Fading Channels, Ahmed Muthana M. Nadhim, Jianhua He, Jiangtao Xi, Zongkai Yang
An Adaptive Scalable Multiuser-Ofdm System For Multimedia Transmission Over Fading Channels, Ahmed Muthana M. Nadhim, Jianhua He, Jiangtao Xi, Zongkai Yang
Faculty of Informatics - Papers (Archive)
In this paper, an adaptive scalable multiuser-OFDM system was proposed for multimedia transmission over fading channels. The proposed adaptive algorithm can adapt according to the channel status information of each user's channel status. This algorithm dynamically changes according to the user's channel changes; this can keep fixed QoS at the physical layer. Another predefined QoS for different sessions and services to be provided for different users. This QoS can be guaranteed by multimedia scalability. Scalability can adapt to the service requirements, in terms of transmission data rate and bandwidth. As a result, a robust multimedia transmission scheme is achieved by …
Peak-To-Mean Power Control In Ofdm, Golay Complementary Sequences, And Reed–Muller Codes, James A. Davis, Jonathan Jedwab
Peak-To-Mean Power Control In Ofdm, Golay Complementary Sequences, And Reed–Muller Codes, James A. Davis, Jonathan Jedwab
Department of Math & Statistics Faculty Publications
We present a range of coding schemes for OFDM transmission using binary, quaternary, octary, and higher order modulation that give high code rates for moderate numbers of carriers. These schemes have tightly bounded peak-to-mean envelope power ratio (PMEPR) and simultaneously have good error correction capability. The key theoretical result is a previously unrecognized connection between Golay complementary sequences and second-order Reed–Muller codes over alphabets ℤ2h. We obtain additional flexibility in trading off code rate, PMEPR, and error correction capability by partitioning the second-order Reed–Muller code into cosets such that codewords with large values of PMEPR are isolated. …